Final answer:
A drive-by download is when a user's browser automatically downloads malicious code from an infected website, exploiting browser vulnerabilities. Users can protect against these by updating software, using security features, and installing antivirus programs.
Step-by-step explanation:
When unsuspecting users visit an infected website and their browsers download code that targets a vulnerability in the user's browser, this type of attack is known as a drive-by download. Hackers exploit security flaws in web browsers or in browser plugins to install malicious software without the user's knowledge or consent. These attacks can occur simply by visiting a website, without any requirement for the user to click on a link or download a file.
Protecting against these attacks usually involves keeping browsers and plugins up-to-date with the latest security patches, enabling click-to-play plugins, and using reputable antivirus and anti-malware software that can detect and block malicious downloads. Additionally, users can benefit from using web browser security features that warn about potentially dangerous sites or block downloads from untrusted sources.